I agree with Laurent.
And I could do with more sigil, which is more controversial.
As much I would like to get rid of the € as a French currency, I would like to have it as sigil for types that are Associative, Positional and Scalar.
Many kinds of tree nodes could have that property. In Perl 6, a match acts like it has these properties but can't advertise it with .^roles (see below).
$/ would be written as €/.
Ironically, a non match is Nil and not Match.
And one successful match value cannot be used as an invocant to .^roles :
'a' ~~ /a/; say $/.^roles
OUTPUT: «(exit code 1) Unexpected named argument 'transitive' passed